NOTES: Nonattainment areas do not meet the national primary or secondary ambient
air quality standard (NAAQS) for the specified pollutant. Nonattainment areas
are classified based on design values: Extreme = design value of 0.280 part per
million (ppm) and above; Severe-17 = design value of 0.190 up to 0.280 ppm and
has 17 years to reach attainment; Severe-15 = design value of 0.180 up to 0.190
ppm and has 15 years to reach attainment; Serious = design value of 0.160 up to
0.180 ppm; Moderate = design value of 0.138 up to 0.160 ppm; Marginal = design
value of 0.121 up to 0.138 ppm; Section 185A = an area designated as an ozone
nonattainment area as of the date of enactment of the Clean Air Act Amendments
of 1990 and has not violated the national primary ambient air quality standard
for ozone for the 36-month period commencing on Jan. 1, 1987, and ending on Dec.
31, 1989.